An HVDC relay comprises a frame and a yoke plate; a chamber for accommodating a stationary contact assembly and a moving contact assembly is formed by the frame and the yoke plate; the stationary contact assembly comprises a leading-out end and stationary contacts; the leading-out end is fixed with the frame and extended to an outer side of the frame, wherein the chamber is to be vacuumized inside and filled with inert gases. In the prior art, most frames are made of plastics or ceramics. Frames made of plastics will be provided with a sealing adhesive to seal the chamber, so as to promise the sealing performance of the chamber. The position where the plastic frame and the yoke plate contact and the position where the leading-out end and an outer side of the frame contact are sealed by the sealing adhesive. With regard to a frame made of ceramics, the stiffness of the product structure is promised by the ceramic itself, so as to ensure the sealing performance of the chamber.
The method in which a plastic frame is sealed by adhesive pouring has advantages such as short manufacturing period, low process requirements and low manufacturing cost. However, in long-term use, the plastic frame will be softened under the influence of temperature, the sealing adhesive will be burned and become yellow under the influence of temperature, and thus there is a risk that inert gases inside the chamber will leak. In addition, under the influence of temperature, the sealing adhesive will expand when heated and contract when cooled; and there will be a gap between the sealing adhesive and the leading-out end, thus leading to explosion.
With regard to a relay with a frame made of ceramics, due to the stiffness of the ceramic frame itself, the long-term use may cause only cracks on the ceramic frame without the risk of explosion. However, for a relays with a ceramic frame, the ceramic frame and the yoke plate as well as the leading-out end and the ceramic frame are to be brazed. Such a relay has relatively long manufacturing period and relatively high manufacturing cost.